Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz (1998) 71, 77-80

M. Schade and C. Sengonca (1998)
Entwicklung, Frassleistung und Beutepräferenz von Hippodamia convergens Guer.-Men. (Col., Coccinellidae) mit Thrips tabaci Lind. (Thys., Thripidae) sowie zwei Aphidenarten als Beute
[On the development, feeding activity and prey preference of Hippodamia convergens Guer.-Men. (Col., Coccinellidae) preying on Thrips tabaci Lind. (Thys., Thripidae) and two species of Aphidae]
Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 71 (4), 77-80
Abstract: Thrips tabaci Lind. is very difficult to control and thus one of the most important pests of leek in Europe. As an alternative to insecticides biological control may be carried out by making use of beneficial insects, the Coccinellidae being one of the most important: predatory families. In the present study laboratory trials were carried out with Hippodamia convergens Guer.-Men., one of the polyphagous representatives of the lady birds, to figure out the feeding activity, development and prey preference of H. convergens against the onion thrips in comparison with two aphid species.
H. convergens developed fully when fed exclusively T. tabaci larvae, although mortality was considerably higher and development took much longer. When fed thrips the complete development lasted 29,8 days on an average, the mortality reaching 88%. When offered Acyrthosiphon pisum (Harris) H. convergens took only 24 days for development with a mortality of only 16%. Above all, the fourth larval instar and the pupa suffered from a very high mortality, reaching 45 and 50% respectively. With A. pisum as a prey mortality decreased to only 6%. The duration of the pupal development was not affected by the prey species.
The feeding activity of H. convergens increased significantly during the development. The larvae of the second and fourth instar predated 28 and 170 thrips larvae respectively per day as a maximum. The adults achieved the highest feeding activity, predating more than 300 thrips larvae in 24 hours. When adding up the number of prey individuals per day for each developmental instar, the L₂ larvae predated more than 90 and the L₄ larvae more than 1000 thrips larvae.
When offered thrips larvae and Myzus persicae (Sulz.) simultaneously, there was an increasing prey preference during the development of H. convergens from first larval instar to adult. As to the last instars there was 20-25% less predation of thrips larvae compared to the aphids during 24 hours.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: German)
Link to article at publishers website
Database assignments for author(s): Michael Schade, Cetin Sengonca

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Acyrthosiphon pisum
	Thrips tabaci	Onion/garlic/leek (Allium)
Hippodamia convergens (predator)	Acyrthosiphon pisum
Hippodamia convergens (predator)	Thrips tabaci	Onion/garlic/leek (Allium)